Preparation of methyl tert-butyl ether (MTBE) over zeolite catalysts

Abstract

Ind. Eng. Chem. Res.It should also be noted that anisole did not show any significant direct demethoxylation under corresponding reaction conditions (Vuori et al., 1984).Effect of Tetralin. As can be seen from Figure 2, for example, tetralin decreases the decomposition rate of each of the model compounds studied. The presence of tetralin was also found to prevent the formation of higher products, excluding experiments with p-hydroxyanisole at 673 K. Obviously this is due to the quenching effect tetralin has on free-radical reactions. The formation of higher products from p-hydroxyanisole, even in the presence of tetralin, can be explained by steric reason. ConclusionsThe reactivity of guaiacol is much greater than the reactivity of any other of the hydroxy-or methoxyanisoles. The reason for this is the hydroxy group at the ortho position, since the reactivity of anisole is also low.Two major primary pathways can be distinquished for d three hydroxyanisoles: the first leading to the formation of the correspondingly substituted dihydroxybenzenes and the second leading to the formation of the correspondingly substituted cresols. For guaiacol, the former pathway may be, in addition to a homolytic bond scission, partly concerted. A concerted mechanism cannot, however, be visualized for m-and p-hydroxyanisoles. The latter pathway is thought to take place via a spiranic oxiran intermediate. Neat m-hydroxyanisole shows, in addition, some formation of methyl-m-hydroxyanisoles. Direct breaking of the aromatic C-0 bonds in the hydroxyanisoles occurs only to a minor extent under mild thermolysis conditions. The o-and p-methoxyanisoles follow a reaction pattern of the same type as the hydroxyanisoles, while m-methoxyanisole gives more ring-methylated products with two oxygen atoms. There is, however, no indication of a concerted mechanism for o-methoxyanisole. The formation of anisole by direct demethoxylation is significant for all three methoxyanisoles, while the presence of a hydroxy group in the hydroxyanisoles seems to prevent this demethoxylation.The decomposition rate of all the model compounds studied is decreased by the presence of tetralin. AcknowledgmentThis work has been funded in part by grants from the Ministry of Education and Neste Oy Foundation. We are 1987,26, 365-369 365 grateful to Eija Kinnunen and Tim0 Karinen for their contributions to the experimental part of this work. Literature Cited Avni, E.; Coughlin, R. W.; Solomon, P. R.; King, H. H. Prepr. Pap.-Am. Chem. SOC., Diu. Fuel Chem. 1983, 28(5), 307-318. Bredenberg, J. B.; Ceylan, R. Fuel 1983, 62, 342-344. Bredenberg, J. B.; Huuska, M.; Toropainen, P. Actas Simp. Iberoam. Ceylan, R.; Bredenberg, J. B. Fuel 1982, 61, 377-382. Connors, W. J.; Johanson, L. N.; Sarkanen, K. V.; Winslow, P. Deglise, X.; Lede, J. Znt. Chem. Eng. 1982, 22, 631-646. Iatridis, B.; Gavalas, R. Ind. Eng. Chem. Prod. Res. Dev. 1979, 18, Jegers, H. E.; Klein, M. T. Ind. Eng. Chem. Process Des. Deu. 1985, Kislitsyn, A. N.; Rodionova, Z. M.; Savinykh, V. I.; Il'ina, E. I.; Abakhumo...

Alternative catalysts for MTBE production

“…Sulfonic ion-exchange resin, which is the usual commercial MTBE synthesis catalyst, has strong protonic acidity. However, other acid catalysts like zeolites [2][3][4][5] and heteropolyacids [6] have shown considerable activity for the reaction.…”

Preparation of methyltert-Butyl ether (MTBE) over heteropoly acids immobilized on activated carbon (HPA/C) in the vapor phase

“…As a result of higher acid strength ofHPA, SiWx2/C gives a superior selectivity to MTBE over the entire range of methanol-to-isobutene ratios compared with Amberlyst-15 catalyst, whose selectivity approaches that of HPA/C only at high MeOH/i-CaHs [7]. For example, for SiWIJC, about 52.1% MTBE is yielded at the lower WHSV of 2.60 h -1 and higher molar ratio of 2.00.…”

The Synthesis of Asymmetrical Tertiary Alkyl Ethers Catalyzed by Ionic Liquids with and without CO2.

“…For example, they are thermally and chemically instable, sensitive to water. Zeolites have been investigated as potential alternative catalysts, but they are less efficient than Amberlyst-15 [8,9]. The main reasons to use solid acids are that their vapor pressure is extremely low and they are insoluble in the reactants and products, which facilitates product isolation.…”